U.S. Pat. No. 3,988,993 discloses a workpiece holder designed for automatic sewing machines, which has a plurality of pick-up and clamping plates for picking up a plurality of workpiece parts to be joined together into one two-dimensional compound workpiece. Since this workpiece holder also acts as a sewing template, it must be of a relatively stable design, as a consequence of which its manufacture is rather expensive. Since the slots through which the needle passes in a sewing template should be spaced as closely as possible to one another, if such a workpiece holder is used for making shoes, it is necessary to provide separate workpiece holders not only for different styles, but even for the different sizes of one and the same style, so that even this leads to an increased expense depending on the number of different styles and sizes. The use of clamping plates with a central, continuous opening for the passage of the needle leads furthermore to the circumstance that the edge distance in the case of edge-parallel seams cannot be reduced below a defined, relatively great-value.
In U.S. Pat. No. 4,557,134 (corresponding to unpublished West German Patent Application No. P 38,37,516.8), a device is used to fix in the correct position on the lower part a plurality of upper parts to be placed on a lower part by bonding, after which the workpiece parts can be sewn together without problems by forming, e.g., an edge-parallel seam at a short distance from the edge. The device contains a central, stationary bench plate for the lower part and a plurality of folding plates for the upper parts, which plate is hinged to the outside of the bench plate, wherein the bench plate and the folding plates are connected to one suction device each for holding the workpiece parts. Before the folding plates are folded over, adhesive is applied by an adhesive applying device onto the upper parts placed on the folding plates in a defined manner. If a plurality of folding plates are needed to pick up a greater number of overlapping workpiece parts or workpiece parts that are placed over one another, these are hinged next to one another to the bench plate having a corresponding polygonal shape, so that the folding plates extend around the bench plate in a wreath-like pattern. However, in the case of a corresponding plate size, such an arrangement leads to difficulties in feeding the distant bench plate, wherein the operator must move to and fro along the folding plates to feed them, and the distance covered by the operator is particularly long because of the arc-shaped arrangement of the folding plates.